An aspect of this invention relates to novel methods of killing cancer cells and inhibiting cancer cell proliferation by treating cancer cells with 3-(2-substituted-ethyl) indole compounds. The National Cancer Institute estimates that as of Jan. 1, 2012, approximately 13.7 million Americans had some history of cancer; some being cancer-free survivors, while others still having evidence of cancer and undergoing treatment. About 1,660,290 new cancer cases are expected to be diagnosed in 2013. Worse yet, in 2013, about 580,350 Americans are expected to die of cancer, almost 1,600 people per day. Cancer is the second most common cause of death in the United States, exceeded only by heart disease. Cancer accounts for nearly 1 of every 4 deaths. The bleak picture becomes brighter: the 5-year relative survival rate for all cancers diagnosed between 2002 and 2008 is 68%, up from 49% from the period 1975-1977. The improvement in survival rates reflects both progress in diagnosing cancer at earlier stages and improving treatment options. The present invention expands the field of treatment options available to those fighting this nefarious disease.
Of all cancer types, colorectal cancer is one of the most frequently diagnosed. Excluding skin cancers, colorectal cancer is the third most common cancer diagnosed in both men and women in the United States. The American Cancer Society projects the following estimates for 2013: 102,480 new cases of colon cancer and 40,340 new cases of rectal cancer. Colorectal cancer is the third leading cause of cancer-related deaths in the United States when men and women are considered separately, and the second leading cause when both sexes are combined. It is expected to cause about 50,830 deaths during 2013.
The odds of surviving cancer increase significantly if the disease is detected in an early localized stage. Unfortunately, only about a third of cancer diagnoses occur at this early stage. To combat later-stage cancer, medical professionals prescribe the following types of treatment: surgery, radiation therapy, chemotherapy, targeted therapy, or any combination thereof. Chemotherapy drugs and targeted therapy drugs are both used to treat cancer. Derivative compounds of such drugs continue to be studied and tested. Indole compounds have been investigated for their putative anticancer properties. For example, indole-3-carbinol is a natural bioactive compound present in cruciferous vegetables such as cabbage, broccoli, and collard greens. Studies have indicated the efficacy of indole-3-carbinol and its acid-induced dimerization product, 3,3′ diindolylmethane (DIM) against various human cancers. Additionally, indole compounds have been shown to have multiple intracellular targets through which they affect cancer cell signaling. These effects are significant with respect to chemosensitization. Indole-3-carbinol, DIM, and various other indole derivatives help reduce the toxicity of and resistance against conventional chemotherapeutic drugs. Both indole-3-carbinol and DIM are well known for their clinical benefits; however, research inversely correlating indole-3-carbinol with the viability of cancer cells is limited and inconsistent.